{
  "schema_version": "1.3.0",
  "slug": "how-should-an-instance-detect-a-manifest-signature-that-verifies-but-was-signed-by-a-rotated-out-key-during-cross-org-agent-trust-bootstrapping",
  "title": "How should an instance detect a manifest signature that verifies but was signed by a rotated-out key during cross-org agent trust bootstrapping",
  "date_of_record": "2026 November 11",
  "scope": "Applies to agent-to-agent trust bootstrapping where a relying party (RP) validates an issuer-org's signed agent manifest and then exchanges verifiable credentials (VCs) with the agent described therein. Does not apply to single-org deployments with a shared key root, nor to bearer-token flows without manifest indirection.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-should-an-instance-detect-a-manifest-signature-that-verifies-but-was-signed-by-a-rotated-out-key-during-cross-org-agent-trust-bootstrapping.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-detect-a-manifest-signature-that-verifies-but-was-signed-by-a-rotated-out-key-during-cross-org-agent-trust-bootstrapping.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-detect-a-manifest-signature-that-verifies-but-was-signed-by-a-rotated-out-key-during-cross-org-agent-trust-bootstrapping.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1471,
    "python_slice_tokens": 363,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure mode is not \"invalid signature.\" A signature that fails to verify is trivially rejected. The non-obvious boundary is a **signature that verifies correctly under a key that is still published in the issuer's JWKS (or DID document), but whose key was rotated out of the *authoritative signing set* for the manifest's declared `issued_at` epoch**. The...",
    "what_was_observed": "Two orgs, A (issuer) and B (relying party), bootstrapped an agent manifest exchange. A rotated its manifest-signing key `K1 → K2` on 2026-10-01, retaining `K1` in its JWKS for a 90-day overlap window to validate *historical* VCs already in the wild. A's rotation policy correctly scoped `K1` to `not_after: 2026-10-01` for *manifest signing* while leaving it valid for *VC verification* until 2026-12-30. On 2026-11-09 a...",
    "condition_of_validity": "The distinction holds only when all of the following are true: 1. The issuer publishes **per-purpose, per-epoch key metadata** — i.e., the JWKS entry carries `key_ops` / a purpose claim (`manifest-signing` vs `vc-verification`) and an epoch bound (`valid_from`/`valid_until`). 2. The manifest carries a **self-asserted `issued_at`** that the verifier must cros...",
    "decision_boundary": "Reject the manifest when **any** of these hold, even though the signature verifies: - The signing key's `manifest-signing` epoch does **not** contain the manifest's `issued_at`. - `issued_at` is earlier than the key's `valid_from` for manifest-signing purposes (key did not yet exist). - `issued_at` is later than the key's `valid_until` for manifest-signing p...",
    "operational_effect": "Relying parties that implement only signature verification will bootstrap trust to attacker-controlled agents roughly whenever an old signing key leaks and the issuer maintains a rotation overlap — a window that, in observed deployments, spans 30–90 days and is exactly when old keys are most exposed (deprecated CI runners, archived secrets). The mitigation i..."
  },
  "matched_failure_symptoms": [
    "DOMAIN:EPISTEMIC_PROVENANCE_AND_FEDERATION_ROUTING"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
    "upstream_precondition_residuals": [
      "https://corpusfetch.com/c/according-to-what-precedence-hierarchy-must-an-instance-resolve-contradictory-directives-across-system-developer-and-user-tiers.md",
      "https://corpusfetch.com/c/how-should-an-instance-decide-that-a-stored-conclusion-has-gone-stale-without-a-new-observation.md"
    ],
    "downstream_consequence_residuals": [
      "https://corpusfetch.com/c/by-what-checkpoint-and-compaction-boundaries-must-an-instance-externalize-working-state-to-prevent-context-window-drift-and-truncation-amnesia.md",
      "https://corpusfetch.com/c/across-what-additive-schema-and-unknown-field-preservation-boundaries-must-an-instance-evolve-wire-contracts-to-prevent-rolling-deploy-deserialization-crashes.md"
    ],
    "co_occurring_sibling_residuals": [
      "https://corpusfetch.com/c/how-can-an-instance-capture-implicit-user-preferences-without-storing-private-data.md",
      "https://corpusfetch.com/c/how-can-an-instance-compress-long-reasoning-traces-into-binding-conclusions.md"
    ]
  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "bfb176d2d49ea121addd53608959b648e0c2e7b59d5d954bb9bf80046f49a4a6",
    "verified_classes": [
      "ManifestEpochError",
      "KeyEpoch",
      "Manifest"
    ],
    "verified_functions": [
      "authorize_manifest",
      "bootstrap_trust"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 6,
    "raised_exceptions": [
      "ManifestEpochError"
    ],
    "sample_fail_closed_invariants": [
      "signature does not verify",
      "manifest valid_from precedes issued_at beyond clock skew"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "datetime"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}